40 lines
1.5 KiB
Java
40 lines
1.5 KiB
Java
package composite;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* Composite — a directory that holds both Files (leaves) and other Directories.
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*
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* getSize() is recursive: asks each child for its size and sums them.
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* print() recurses with deeper indentation.
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*
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* The caller doesn't care whether a child is a File or Directory —
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* both answer getSize() and print() the same way.
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*/
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public class Directory implements FileSystemItem {
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private final String name;
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private final List<FileSystemItem> children = new ArrayList<>();
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public Directory(String name) { this.name = name; }
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// Fluent add() — allows chaining: dir.add(file1).add(file2).add(subDir)
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public Directory add(FileSystemItem item) {
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children.add(item);
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return this;
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}
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public void remove(FileSystemItem item) { children.remove(item); }
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@Override public String getName() { return name; }
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@Override
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public long getSize() {
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// Each child knows its own size: files return bytes, directories recurse.
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// This is the Composite's core: uniform delegation down the tree.
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return children.stream()
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.mapToLong(FileSystemItem::getSize)
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.sum();
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}
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@Override
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public void print(String indent) {
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System.out.printf("%s[DIR] %s/ (%,d bytes total)%n", indent, name, getSize());
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for (FileSystemItem child : children) {
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child.print(indent + " "); // each level indents 4 more spaces
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}
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}
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}
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